What is a significant factor contributing to carbon monoxide production in gas appliances?

A significant factor contributing to carbon monoxide production in gas appliances is incomplete combustion due to insufficient air supply. When a gas appliance operates, it requires a specific amount of oxygen to burn the gas completely. If there isn't enough oxygen available, the combustion process is disrupted, leading to the formation of carbon monoxide, a toxic byproduct. This is particularly critical in residential settings where proper ventilation may not be ensured, increasing the risk of carbon monoxide buildup.

In contrast, while excessive gas pressure can affect the performance of gas appliances, it isn't directly linked to an increase in carbon monoxide production. Similarly, old gas meters may affect the measurement of gas flow but do not inherently cause incomplete combustion. Lastly, poor quality fuel can affect efficiency and performance but is more likely to lead to inefficiencies rather than directly causing carbon monoxide production like insufficient air supply does.